Jeff's bloghttp://www.connecticuthackerspace.com/blogs/jeff
ConnecticutHackerspace.com FeedenCapacitive Discharge Battery Tab Spot Welderhttp://www.connecticuthackerspace.com/content/capacitive-discharge-battery-tab-spot-welder
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p>Things are coming together on my latest project, a capactive discharge spot welder intended to be used for welding battery tabs. I will be creating a project page shortly to document the entire process but wanted to put something up tonight as I have made some significant progress on the project tonight. Here is a quick look at how the device is coming together.</p>
<p> </p>
<p style="text-align: center;"><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2013-01-02%2021.16.57.jpg" /></p>
<p style="text-align: left;">The device is basically comprised of (2) .75 Farad Capacitors, a 24V DC Power supply, a large SCR, a foot pedal and a set of electrodes. All of the components are currently cased in a repurposed power tool carrying case. Some preliminary proof of concept welds have been completed but some tweeking is still necessary.</p>
<p style="text-align: left;">Check the project page soon for a full write up.</p>
</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Thu, 03 Jan 2013 04:13:05 +0000Jeff526 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/capacitive-discharge-battery-tab-spot-welder#commentsNew Phone Charging Station write-uphttp://www.connecticuthackerspace.com/content/new-phone-charging-station-write
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p>I encourage everyone to take a look at the great write up that Rich put together for the Phone Charging station that he built featured in our projects section <a href="http://www.connecticuthackerspace.com/content/phone-charging-station-0 ">HERE </a></p>
<p style="text-align: center;"><img alt="" class="media-image" height="480" width="321" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/charger04.jpg" /></p>
<p>Great Job on the charging station Rich and a nice write up to boot.</p>
</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Wed, 02 Jan 2013 01:44:37 +0000Jeff525 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/new-phone-charging-station-write#commentsCNC Engraver/Mini Millhttp://www.connecticuthackerspace.com/content/cnc-engravermini-mill
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p> I think I am now at the point wher I can deem the Mini CNC Mill/Engraver operational again. We had the machine functioning well imediately after the build was complete using a borrowed control set-up but that stepper driver set has since gone back to its owner. In the time sense, I have been working on a "universal" stepper driver/parallel port break out board set up that could be use for this machine. I have had a few issues to troubleshoot but I feel as though I can now say that my "universal' stepper driver/break out board is functional with this machine. </p>
<p>Members that have been interested in using this machine should contact me for instructions on how to operate it with my stepper driver/break out board. For those that are intersted in using it but currently have no CNC programming experience, I am considering holding a workshop to introduce people to the basics of CNC operation. Anyone interested in such a workshop should contact me as well so that we can firm up plans for this workshop.</p>
<p> </p>
</div></div></div><div class="field field-name-taxonomy-vocabulary-2 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Login Types:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/16">Active Member</a></div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Wed, 25 Jul 2012 03:57:18 +0000Jeff490 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/cnc-engravermini-mill#commentsProgress on Large CNC Router Stepper Drivers http://www.connecticuthackerspace.com/content/progress-large-cnc-router-stepper-drivers
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p style="text-align: left; ">Had some time tonight to solder together the stepper drivers for the Large Format CNC router. All components are now soldered except for the power transistors which I need to layout on the heatsink in a way that duplicates how the drivers will be mounted in the chasis so that the locations all work out correctly. </p>
<p style="text-align: center; "> <img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-07-24%2022.29.38.jpg" /></p>
<p style="text-align: center; ">3 Axes connected to the breakout board</p>
<p style="text-align: center; "><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-07-24%2022.29.49_0.jpg" /></p>
<p style="text-align: center; ">Stepper driver less the PIC and the power transistors. </p>
</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Wed, 25 Jul 2012 03:38:16 +0000Jeff489 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/progress-large-cnc-router-stepper-drivers#commentsMy Current Raspberry Pi set-uphttp://www.connecticuthackerspace.com/content/my-current-raspberry-pi-set
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p> Although I have not had as much time to mess around with my Raspberry Pi as I would like, I have come up with a set-up that allows me to work with it a little more easily. I had found that I was avoiding working with the Pi because I didn't have a monitor that accepted composite video or HDMI in a place that was conducive to working with the Pi. Recently while trolling the electronics area at the local dump, I came across a display with built in speakers that I believe was intended for use with the Play Station 2. </p>
<p style="text-align: center; "><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-07-15%2020.34.49.jpg" /></p>
<p style="text-align: center; "> </p>
<p style="text-align: left; ">As you can see from the picture above, the screen size is quite small. The picture clarity is actually quite good though. I will have to say that this is not an ideal set-up; I would not attempt to hack on the Pi for hours at a time using this but it does fill my current need to have something small and portable that I can set-up quickly. So far, I have set-up two SD cards; one with a Debian install and a second with the OpenElec distribution which provides XBMC. </p>
<p style="text-align: left; "> </p>
<p style="text-align: center; "><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-07-15%2020.35.07.jpg" /></p>
<p style="text-align: center; "> OpenELEC XBMC Main Screen</p>
<p style="text-align: left; "> </p>
<p style="text-align: left; ">Future plans include possibly hacking the case of this display to fit the Raspberry Pi inside. I also expect to start working with the GPIO on the Pi to see what fun can be had. I actually wish that I had two of these as I would likely set one up semi-permanently as a set-top unit with XBMC while keeping a second around for general hacking. </p>
</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Mon, 16 Jul 2012 01:25:10 +0000Jeff480 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/my-current-raspberry-pi-set#commentsRetractable Extension Cord from Discarded Vacuumhttp://www.connecticuthackerspace.com/content/retractable-extension-cord-discarded-vacuum
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p>Recently we were talking at the hackerspace about how convenient retractable extension cords are while at the same time lamenting the high cost. As is often the case, the conversation ended with all in agreement that they cost too much to buy on a shoestring budget and the thought died then and there. </p>
<p>Fast forward a few weeks to one of my regular Saturday, father/son trip to the dump which always includes a quick review of the items that are set aside for "take it or leave it". This particular week there was a Harbor Freight handheld vacuum cleaner which my son was sure that he wanted to take to the hackerspace to take apart. I grabbed it up knowing tha tthe worst case would be me returning it to the dump in many more pieces.</p>
<p>Upon getting to the hackerspace, we found that the vacuum was perfectly functional however my son really wanted to take it apart. After a quick review of the vacuum canister, it was clear that the 1-2 cup capacity of the canister made the unit practically useless for the messes I typically make and need to clean up. So the vacuum fell prey to rapid disassembly at the hand of a curious 6 year old with a bunch of screwdrivers and pliers at hand.</p>
<p>After full diassembly the vacuum was reduced to its most basic components. Jonah was proud that he was able to extract the motor and remove the impeller from the motor. This will hopefully be useful in a future project. With all of the parts on the table I noticed that this vacuum had a built in, spring loaded , cord reel. Just then, I remembered the coversation that occured in the exact same spot several weeks before regarding retractable extension cords. After asking Jonah if I could have the left over pieces, I got to work.</p>
<p>Initially, I thought of extracting the cord reel from the case and putting it into something more compact. After staring at it for a while, I convinced myself that using the existing case would be easier as it provided a place to mount a standard outlet as well as a on/off switch which I thought would come in handy from time to time. A few minutes later, I had all of the parts collected together and started cutting a hole for the outlet. The wiring was straight forward,the wires previously routed to the motor were connected to the outlet and I had a switched outlet with a retractable extension cord.</p>
<p>The pictures show the results. While it does hace some limitations, it has already come in quite handy. Knowing that the ground plug receptical is not connected through the cord, I am sure to only power 2 prong devices with this cord. I intend to replace the whole recepticle with a 2 prong one shortly. </p>
<p style="text-align: center;"><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-07-15%2010.22.36_0.jpg" /></p>
<p style="text-align: center;"> </p>
<p style="text-align: center;"><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-07-15%2010.23.46.jpg" /></p>
<p>I also am looking at putting a mechanical timer switch in parallel with the on/off switch for when I am using it to power a soldering iron. The mechanical timer will turn the power off to the iron in the case that I get distracted and forget to uplug/turn off the iron.</p>
</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Sun, 15 Jul 2012 17:25:53 +0000Jeff479 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/retractable-extension-cord-discarded-vacuum#commentsPictures from Arduino Workshop -6/23/12http://www.connecticuthackerspace.com/content/pictures-arduino-workshop-62312
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p style="text-align: center; "> <img alt="" class="media-image" height="360" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/ArduinoWorkshop_120623-1.JPG" /></p>
<p style="text-align: center; ">A great group for the workshop today!</p>
<p style="text-align: center; "><img alt="" class="media-image" height="360" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/ArduinoWorkshop_120623-3.JPG" /></p>
<p style="text-align: center; ">A freshly soldered Arduino plugged in and ready to be programmed.</p>
</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Sun, 24 Jun 2012 03:11:39 +0000Jeff476 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/pictures-arduino-workshop-62312#commentsSome more Molex connectors that I may be using soon at the space. http://www.connecticuthackerspace.com/content/some-more-molex-connectors-i-may-be-using-soon-space
<div class="field field-name-upload field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><table class="sticky-enabled">
<thead><tr><th>Attachment</th><th>Size</th> </tr></thead>
<tbody>
<tr class="odd"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/0003091041_CRIMP_HOUSINGS%20%28Molex%201490%29.pdf" type="application/pdf; length=39422">0003091041_CRIMP_HOUSINGS (Molex 1490).pdf</a></span></td><td>38.5 KB</td> </tr>
<tr class="even"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/03091049_CRIMP_HOUSINGS%20%28Molex%202163R%29.pdf" type="application/pdf; length=40856">03091049_CRIMP_HOUSINGS (Molex 2163R).pdf</a></span></td><td>39.9 KB</td> </tr>
<tr class="odd"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/0003091157_CRIMP_HOUSINGS%28Molex%2015%20Pin%20Receptical%29.pdf" type="application/pdf; length=38355">0003091157_CRIMP_HOUSINGS(Molex 15 Pin Receptical).pdf</a></span></td><td>37.46 KB</td> </tr>
<tr class="even"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/03092049_CRIMP_HOUSINGS%20%28Molex%202163P%29.pdf" type="application/pdf; length=40610">03092049_CRIMP_HOUSINGS (Molex 2163P).pdf</a></span></td><td>39.66 KB</td> </tr>
<tr class="odd"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/Molex1490-ConnectorsDatasheet.pdf" type="application/pdf; length=417007">Molex1490-ConnectorsDatasheet.pdf</a></span></td><td>407.23 KB</td> </tr>
<tr class="even"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/1189_CRIMP_TERMINALS.pdf" type="application/pdf; length=32560">1189_CRIMP_TERMINALS.pdf</a></span></td><td>31.8 KB</td> </tr>
<tr class="odd"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/1190_CRIMP_TERMINALS.pdf" type="application/pdf; length=35273">1190_CRIMP_TERMINALS.pdf</a></span></td><td>34.45 KB</td> </tr>
<tr class="even"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/1380_CRIMP_TERMINALS.pdf" type="application/pdf; length=35274">1380_CRIMP_TERMINALS.pdf</a></span></td><td>34.45 KB</td> </tr>
<tr class="odd"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/1381_CRIMP_TERMINALS.pdf" type="application/pdf; length=34801">1381_CRIMP_TERMINALS.pdf</a></span></td><td>33.99 KB</td> </tr>
<tr class="even"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/1433_CRIMP_TERMINALS.pdf" type="application/pdf; length=35330">1433_CRIMP_TERMINALS.pdf</a></span></td><td>34.5 KB</td> </tr>
<tr class="odd"><td><span class="file"><img class="file-icon" alt="" title="application/pdf" src="/modules/file/icons/application-pdf.png" /> <a href="http://www.connecticuthackerspace.com/sites/default/files/1434_CRIMP_TERMINALS.pdf" type="application/pdf; length=34385">1434_CRIMP_TERMINALS.pdf</a></span></td><td>33.58 KB</td> </tr>
</tbody>
</table>
</div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <div style="text-align: center; "><span style="font-size: larger; "><strong>Some more Molex connectors that I may be using soon at the space. </strong></span></div>
<div style="text-align: center; "> </div>
<div style="text-align: center; "><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-06-02%2015.51.38_0.jpg" /></div>
<div> </div>
<div>15 Pin Molex 2159/1159:</div>
<div>Use With:</div>
<div>1189 Crimp Terminals, 1190 Crimp</div>
<div>Terminals, 1376 Male PC Tail Terminals,</div>
<div>1377 Female PC Tail Terminals, 1380</div>
<div>Male Crimp Terminals, 1381 Female Crimp</div>
<div>Terminals, 1433 Crimp Terminals, 1434</div>
<div>Male Crimp Terminals, 1973</div>
<div> </div>
<div style="text-align: center; "><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-06-02%2015.51.58.jpg" /></div>
<div>4 Pin 2x2 Molex 2163 P &amp;R:</div>
<div>Use With:</div>
<div>1189 Crimp Terminals, 1190 Crimp</div>
<div>Terminals, 1380 Male Crimp Terminals,</div>
<div>1381 Female Crimp Terminals, 1433 Crimp</div>
<div>Terminals, 1434 Male Crimp Terminals,</div>
<div>1973 , 2151 , 2273 , 2870 , 2871 , 4272 ,</div>
<div>4550 , 6271</div>
<div> </div>
<div style="text-align: center; "><img alt="" class="media-image" height="287" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/2012-06-02%2015.51.48.jpg" /></div>
<div> </div>
<div>4 Pin Inline Molex 1490P &amp; R :</div>
<div>Use WIth</div>
<div>1189 Crimp Terminals, 1190 Crimp</div>
<div>Terminals, 1376 Male PC Tail Terminals,</div>
<div>1377 Female PC Tail Terminals, 1380</div>
<div>Male Crimp Terminals, 1381 Female Crimp</div>
<div>Terminals, 1433 Crimp Terminals, 1434</div>
<div>Male Crimp Terminals, 1973</div>
<div>Reference - Drawing Numbers</div>
<div>Product Specification</div>
<div>Sales Drawing</div>
<div>China RoHS</div>
<div>PS-02-09, PS-42477, PS-43660-9999</div>
<div>SD-1490-*</div>
<div> </div>
</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Sun, 03 Jun 2012 01:04:18 +0000Jeff463 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/some-more-molex-connectors-i-may-be-using-soon-space#comments555 Oscillator Buildhttp://www.connecticuthackerspace.com/content/555-oscillator-build
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p> Recently I have been messing around with a lot of motor control circuitry that requires a pulsed input signal. While I coud have whipped up a quick arduino sketch to generate a pulsed output signal, it seemed like overkill. Also, this is something that I wanted to have available as needed without having to flash an arduino etc. </p>
<p>Since I have a boat load of 555 chips and 555's are basically intended to provide a pulsed output, I decided to throw together a quick circuit to use the 555 in astable mode with a potentiometer to control the timing. There are a ton of well documented descriptions of this circuit on the web such as this one: <a href="http://www.electronics-tutorials.ws/waveforms/555_oscillator.html">www.electronics-tutorials.ws/waveforms/555_oscillator.html</a> so I won't get into describing the circuit here. I will show the results below however. </p>
<p>The design incorporates a 9v battery as a power source, a potentiometer to adjust the timing, an LED to visually show the timing and a set of test leads with aligator clips to attach the oscillator to other devices as an input.</p>
<p> </p>
<p style="text-align: center; "><img alt="" class="media-image" height="360" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/555_VariableOscillator1.jpg" /></p>
<p style="text-align: center; "><img alt="" class="media-image" height="360" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/555_VariableOsciillator2.jpg" /></p>
<p style="text-align: center; "><img alt="" class="media-image" height="263" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/555VariableOscillator_120527_0.png" /></p>
</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Tue, 29 May 2012 02:51:44 +0000Jeff459 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/555-oscillator-build#commentsDIY Probe for Sound Card Oscilliscopehttp://www.connecticuthackerspace.com/content/diy-probe-sound-card-oscilliscope
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p style="text-align: left; ">I have recently found myself interested in being able to see the output of various devices having signals that require an oscilloscope to view. I had seen a sound card oscilloscope working on one of our public computers at the space but wanted something to use on my laptop. I also wanted to be sure that I didn't blowout the sound card or mother board on my laptop. </p>
<p style="text-align: left; ">After some research, I came up with the basic design shown here: <a href="http://www.ladyada.net/library/equipt/diyaudioprobe.html">www.ladyada.net/library/equipt/diyaudioprobe.html</a> and was able to build the probe shown below. Having the ability to attenuate the signal down to reasonable levels along with the decoupling capacitor, I felt a little bit more confortable pluggin this into my laptop and firing up Xoscope to look at some signals.</p>
<p style="text-align: center; "> <img alt="" class="media-image" height="360" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/SoundCardScopeProbe.jpg" /></p>
<p style="text-align: center; "><strong>Simple Probe for use with sound card oscilliscope software. </strong></p>
<p style="text-align: center; "> </p>
<p style="text-align: left; ">After thinking about this design at length, I realized that even though the potentiometer allows me to bring the signal down to a reasonable maximum voltage, the probe really does little to protect against the unexpected. Or even if I mistakenly start our with the potentiometer all the way "up". With this in mind, I want to add some 2.1V Zener diodes. Unfortunately, the local store only had 5.1 v zeners so I figured I would wait until I can get what I really want to use. Below are some screen shots of this probe being used in conjunction with Xoscope.</p>
<p style="text-align: left; "> </p>
<p style="text-align: center; "><img alt="" class="media-image" height="263" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/PrinterMotorEncoder_120527.png" /> </p>
<p style="text-align: center; "><strong> Motor Encoder Output</strong></p>
<p style="text-align: center; "><img alt="" class="media-image" height="263" width="480" src="http://www.connecticuthackerspace.com/sites/default/files/styles/large/public/555VariableOscillator_120527.png" /></p>
<p style="text-align: center; "><strong>Output from 555 Based Variable Oscillator </strong></p>
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<p style="text-align: left; ">Overall this works pretty well. Interestingly, I cannot scope a steady state DC Signal. This is supposed to be a limitation of most soundcard based oscilloscopes. I think that this issue is shown in the above view of the 555 based variable oscillator. In a normal scope, the trace would clearly be a square wave. I believe that what is happening here is that the scope does not "trace" steady state voltage so we just see a vertical line above zero for the leading edge of the square wave and a vertical line below zero for trailing edge of the square wave. </p>
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<p style="text-align: left; ">I will definitely be adding the Zener Diodes as soon as I can get them. I may also get 2 smaller pots and mount them in a box or on a board and set up a 2 channel probe. </p>
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</div></div></div><div class="field field-name-taxonomy-vocabulary-3 field-type-taxonomy-term-reference field-label-above"><div class="field-label">Access:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/18">Public</a></div></div></div>Mon, 28 May 2012 22:43:35 +0000Jeff458 at http://www.connecticuthackerspace.comhttp://www.connecticuthackerspace.com/content/diy-probe-sound-card-oscilliscope#comments